Liquid two-component coating compositions

ABSTRACT

This invention relates to coating compositions including one or more resins having amino-reactive groups; one or more polyamine curing agents; and one or more aminourethanes. The aminourethanes can be reaction products of (i) oligomeric or polymeric compounds which contain at least one, preferably two or more terminal 2-oxo-1,3-dioxolane groups (cyclic carbonate groups), and (ii) amines containing at least one primary, preferably two or more primary and, if desired, also secondary and tertiary amino groups. The ratios of equivalents of C1):C2) typically is from 1:1 to 1:10, preferably from 1:1.05 to 1:5 and particularly preferably from 1:1.1 to 1:2, and the end product preferably contains one or more free primary amino groups. The composition further may contain, if desired, pigments, fillers, one or more organic solvents, water and conventional additives.

This application is a division of application Ser. No. 08/358,744, filedDec. 19, 1994 now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to liquid two-component coating compositions basedon amino-reactive resins, polyamine curing agents and aminourethanes.The coating compositions are useful in the coating of a wide variety ofarticles, especially in industrial coatings, automotive finishing andthe coating of automotive components.

2. Description of Related Art

Because of environmental regulations, which are becoming more and morestringent, aqueous systems are gaining increasing importance for use incoating articles. In terms of their properties, they must be measuredagainst conventional, i.e. solvent-containing systems. In this context,water-dilutable epoxy resin systems have gained importance amongcold-curing water-based coating systems. These two-component systemshave outstanding properties. The following positive properties are to beemphasized: little or no solvent content, not a fire hazard, little orno odor, ease of processing, low degree of sensitivity toward moistsubstrates, good drying and rapid through-hardening, excellent adhesionto most substrates, very good intercoat adhesion, good protection ofmetals against corrosion, and easy cleaning of equipment directly afteruse.

Nonionically dispersed epoxy resin systems, as described in DE-A 3 643751, together with aqueous amine-based curing agents specified in EP-A 0000 605, exhibit these outstanding properties and can therefore be usedin a versatile manner as coating compositions. The disclosure of thesedocuments and all other documents mentioned herein are incorporatedherein by reference in their entirety. A disadvantage of these systems,however, is that they do not produce defect-free surfaces in certainapplications.

EP-A 0 523 610 describes aqueous two-component systems based onepoxy/amines, which overcome the above-mentioned disadvantage by theaddition of water-soluble or water-dilutable polyurethane resins. Thesystem described in this document also brings about a high surfacequality. These systems are intended to be used primarily in automotiverefinishing. The disadvantage of these coatings, which are in particularfillers and primers, however, is that they have an inadequatesandability after a short drying time. Such systems are in general muchtoo soft and, because of the pronounced thermoplasticity, after a shorttime the sand paper exerts a severe effect and the surface is damaged.

EP-A 0 234 395 describes aminourethane resins which are obtained byreacting carbonates with compounds having primary amino groups andfurther basic groups. Because of the incorporation of, for example,partially blocked polyisocyanates, these resins may be self-curing.However, it also is possible to add to the aminourethanes a curing agentwhich is conventional for coating systems which crosslink by means ofexternal agents, for example, blocked polyisocyanates, β-hydroxy estersof at least difunctional polycarboxylic acids, transesterificationcuring agents or Michael addition products. The aminourethanes arepreferably employed, after at least partial neutralization, as resinsfor electrodeposition coating. There is only a very general indicationthat the aminourethane resins can also be employed in, preferablynonaqueous, coating systems containing epoxy resin. More precise detailsof the composition, use and properties of these coating systems are notgiven.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to providepolyamine-crosslinking coating compositions which can be cured at roomtemperature, which have a very good surface quality and which, after ashort drying time, can be dry- or wet-sanded and which also show in thinlayers a good adhesion to the substrate.

In accordance with these objectives, there is provided a two-componentcoating composition which can be curable at room temperature, comprising

(A) one or more resins having amino-reactive functional groups;

(B) one or more polyamine curing agents;

(C) one or more aminourethanes which are reaction products of;

(C1) oligomeric or polymeric compounds containing at least one,preferably two or more terminal 2-oxo-1,3-dioxolane groups; and

(C2) amines containing at least one primary, preferably two or moreprimary and, if desired, also secondary and tertiary amino groups; and

(D) optionally, pigments, fillers, solvents, water and conventionaladditives, and in which the ratios of numbers of functional groups in C1and C2, i.e. 2-oxo-1,3-dioxolane groups to primary amino groups, arefrom 1:1 to 1:10, preferably from 1:1.05 to 1:5 and particularlypreferably from 1:1.1 to 1:2.

In accordance with an additional object of the invention there areprovided aqueous coating compositions which comprise water-soluble orwater-dilutable epoxy resins and water-soluble or water-dilutablepolyamine curing agents. These and other objects of the invention willbe readily apparent to those skilled in the art upon review of thedetailed description of the invention that follows.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The ratio of numbers of functional groups of polyamine curing agents(B): aminourethane (C) is generally from 5:95 to 95:5. The ratiopreferably is from 20:80 to 80:20 and particularly preferably from 30:70to 70:30.

The polyamines useful as components (C2) preferably have the formula##STR1## in which R¹ is a divalent hydrocarbon radical, preferably astraight-chain or branched alkylene radical having 2 to 18 carbon atoms,preferably 2 to 4 carbon atoms,

R² is hydrogen, alkyl having 1 to 8 carbon atoms, preferably 1 to 4carbon atoms, or hydroxyalkyl having 1 to 8 carbon atoms, preferably 1to 2 carbon atoms, in the alkyl radical,

R³ is selected from the same groups of residues as R², and R² and R³ mayalso form a cyclic ring compound, preferably a 5-, 6- or 7-memberedaliphatic ring,

or, if R² is hydrogen, R³ may also be a group of the formula

C₁ to C₁₈ --alkyl--COO--CH₂ --CH(OH)--CH₂ --,

C₁ to C₁₈ --alkyl--O--CH₂ --CH(OH)--CH₂ --,

NC--CH₂ --CH₂ -- or

C₁ to C₁₈ --alkyl--CHOH--CH₂ --,

and A is a chemical bond or is --(R¹ --NH)_(r) --R¹ NH in which r iszero or an integer from 1 to 6 and R¹ is as defined above.

Examples of polyamines useful in the invention includepoly-alkyleneamines, such as ethylenediamine, diethylenetriamine,triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine,propylenediamine, dipropylenetriamine etc., and also 2,2,4- and/or2,4,4-trimethylhexamethylenediamine, bis(3-aminopropyl)amine,N,N-bis(3-aminopropyl)ethylenediamine, neopentanediamine,2-methyl-1,5-pentanediamine, 1,3-diaminopentane, hexamethylenediamineetc., and also cycloaliphatic amines such as 1,2- or1,3-diaminocyclohexane, 1,4-diamino-3,6-diethylcyclohexane,1,2-diamino-4-ethylcyclohexane, 1-cyclohexyl-3,4-diaminocyclohexane,isophoronediamine and reaction products thereof,4,4'-diaminodicyclohexylmethane and -propane,2,2-bis(4'-aminocyclohexyl)methane and -propane,3,3'-dimethyl-4,4'-diaminodicyclohexylmethane,3-amino-1-cyclohexylaminopropane, 1,4-bis(3-aminopropyl)piperazine, 1,3-and 1,4-bis(aminomethyl)cyclohexane.

Araliphatic amines which can be employed are, in particular, those inwhich aliphatic amino groups are present, for example meta- andpara-xylylenediamine or hydrogenation products thereof.

Other suitable polyamines include amine-epoxy adducts, for examplereaction products of polyamines, for example ethylenediamine,propylenediamine, hexamethylenediamine, 2,2,4- or2,4,4-trimethylhexamethylenediamine, meta-xylylenediamine and/orbis(aminomethyl)cyclohexane with terminal mono- or polyepoxides, forexample propylene oxide, hexene oxide or cyclohexene oxide, or withglycidyl ethers such as phenyl glycidyl ether, tert-butyl glycidylether, ethylhexyl glycidyl ether or butyl glycidyl ether, or withglycidyl esters, such as the glycidyl ester of ®Versatic acid marketedby Shell, Cardura® E, or the polyglycidyl ethers and esters specifiedbelow (for (C1)).

In addition to the above-mentioned polyamines, it also is possible toemploy water-soluble polyoxyalkylenediamines andpolyoxyalkylenepolyamines having molar masses of from 100 to 2000 g/mol,for example, the products marketed by Texaco under the trade nameJeffamine®, and the readily water-dispersible curing agents as describedin DE-A 23 32 177 and EP-A 0 000 605. These useful polyamines include,for example, modified amine adducts. The polyamines can be used toincrease the hydrophilicity and therefore the solubility ordispersibility of the aminourethanes in water or in aqueous amine curingagents.

The specified amines useful as compounds (C2) can be used alone or asmixtures. In any case the amines should be selected such that the endproduct contains preferably at least one, but particularly preferably,two or more free primary amino groups.

The compounds (C1) having at least one, and preferably at least two2-oxo-1,3-dioxolane groups (=cyclic carbonate groups) can be obtained byreacting carbon dioxide with epoxy compounds in a known manner (see e.g.WO 84/03701, DE-A 3 529 263 and DE-A 3 600 602). The epoxy compoundspreferably are polyglycidyl ethers based on polyhydric, preferablydihydric, alcohols, phenols, hydrogenation products of these phenolsand/or on novolaks (reaction products of mono- or polyhydric phenolswith aldehydes, especially formaldehyde, in the presence of acidiccatalysts). The molar mass divided by the number of epoxy groups(epoxide equivalent masses) of these epoxy compounds preferably arebetween 100 and 2000 g/mol, in particular between 100 and 350 g/mol.

Examples of polyhydric phenols include resorcinol, hydroquinone,2,2-bis(4'-hydroxyphenyl)propane (bisphenol A), isomer mixtures ofdihydroxydiphenylmethane (bisphenol F), tetrabromobisphenol A,4,4'-dihydroxydiphenylcyclohexane,4,4'-dihydroxy-3,3'-dimethyldiphenylpropane, 4,4'-dihydroxybiphenyl,4,4'-dihydroxybenzophenone,1, 1 -bis(4'-hydroxyphenyl)ethane2,2-bis4'-(2"-hydroxypropoxy)phenyl!propane,1,1-bis(4'-hydroxyphenyl)isobutane,2,2-bis(4'-hydroxy-tert-butylphenyl)propane,bis(2-hydroxynaphthyl)methane,1,5-dihydroxynaphthalene,tris(4-hydroxyphenyl)methane,bis(4-hydroxyphenyl)ether, bis(4-hydroxyphenyl) sulfone etc., and also the halogenation andhydrogenation products of the above-mentioned compounds. Bisphenol A isparticularly preferred in this regard.

Examples of polyhydric alcohols include ethylene glycol, diethyleneglycol, triethylene glycol, polyethylene glycols (n=4 to 35),1,2-propylene glycol, polypropylene glycols (n=2 to 15), 1,3-propyleneglycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol,1,2,6-hexanetriol, glycerol, neopentylglycol, trimethylolethane andtrimethylolpropane. Polyethylene glycols (n=8 to 10) are particularlypreferred in this regard.

The reaction of the polyamines (C2) with the cyclic carbonates (C1)preferably is carried out using stoichiometric ratios, and can beeffected using conventional methods at elevated temperatures, ifdesired, with the use of inert solvents. Reaction in the presence ofsolvents which are inert toward the cyclocarbonate group is a preferredprocess variant. The basis for the stoichiometric evaluation of both thestarting products and the end products, and for monitoring the reaction,is the amine number, (measured by titration with perchloric acid) andthe cyclocarbonate equivalents number, (measured by titration withpotassium hydroxide solution). The polyamine compounds can be employedindividually or as mixtures, simultaneously or in chronologicalsuccession, and dissolved if desired in inert solvents.

With regard to the reaction, care should be taken to ensure that thereaction conditions and process conditions observed are those underwhich the cyclocarbonate groups of component (C1) can only react withthe primary amino groups of the other component (C2). This can beachieved by known methods, without corresponding reactions also takingplace with any secondary amino groups which may be present, which areconsiderably slower to react. In addition, excessively high temperaturesshould be avoided, in order to prevent the formation of cyclic ureaderivatives from urethane structures of polyalkylenepolyamines. Thoseskilled in the art are capable of reacting compounds (C1) with compounds(C2) in the aforementioned manner using techniques known in the art.

Examples of suitable inert solvents for this reaction include aromatichydrocarbons such as xylene and toluene, alcohols such as butanols andpentanols, and glycol ethers such as methoxyethanol, ethoxyethanol,methoxypropanol, butoxyethanol, methoxybutanol, glycol dimethyl ethersand diglycol dimethyl ethers and the like. The solvents to be chosenpreferably are those which can be removed readily by distillation afterthe reaction has taken place or which do not interfere subsequently withthe aqueous formulation. In the latter case the solvents should only beused in a quantity which is sufficient to lower the viscosity to amanageable level. Because of their potential reactivity with thereactive components, esters and ketones are of only limited suitabilityand should be tested in each individual case.

The reaction temperature typically can be within the range from 50° C.to 150° C., its lower limit being determined by solubility and viscosityand its upper limit by the tendency to produce secondary reactions andfollow-on reactions and by the boiling point of the solvent. It ispreferred to carry out the reaction at a temperature in the range ofbetween 80° C. and 130° C. Catalysts are not required for this reaction.For instance, reactions between carbonates and primary amines proceedrapidly even at room temperature; however, relatively high temperaturesare usually used for the systems described, since the products oftenhave a high viscosity even in solution.

The relative proportions of (C1) and (C2) should preferably be chosen soas to form amino-functional reaction products which, via thesefunctions, are able to react with amino-reactive functional groups,preferably with the glycidyl groups of an epoxy resin. These groups arepreferably primary amino groups, of which at least one, but even morepreferably, two or more, are present in one molecule of theaminourethane. By varying the proportions of components, it is possibleto obtain products whose character ranges from oligomeric to polymeric,with oligomers being particularly preferred. It is therefore preferredto employ proportions of carbonate to polyamine which are in the regionof about 1 mol of polyamine per mole of carbonate groups in thecomponent.

The aminourethanes (C) obtained in this manner can preferably beemployed, in combination with conventional aqueous amine curing agents(B), as curing and/or modifying agents for aqueous epoxy resin systems.Such amine curing agents, preferably for curing at room temperature andlower temperatures (amine cold curing agents), which are generallyemployed in a ratio of epoxide groups to amine hydrogen atoms of from1:0.75 to 1:2.0, are all of the amines or Mannich bases andpolyamidoamines which have already been mentioned above, which can beused alone or in the form of mixtures. Suitable Mannich bases can beprepared using known methods such as by condensation of polyamines,preferably diethylenetriamine, triethylenetetramine, isophoronediamine,2,2,4- or 2,4,4-trimethylhexamethylenediamine, 1,3- and1,4-bis(aminomethyl)cyclohexane, especially meta- andpara-xylylenediamine, with aldehydes, preferably formaldehyde, and mono-or polyhydric phenols having at least one ring position which isreactive toward aldehydes, for example the various cresols and xylenols,para-tertbutylphenol, resorcinol, 4,4'-dihydroxydiphenylmethane or4',4"-dihydroxy-2,2-diphenylpropane, but preferably phenol. Suitablepolyamidoamines are obtained, for example, by reacting polyamines withmono- or polycarboxylic acids, for example, dimerized fatty acids.

Other suitable amine curing agents (B) which can be employed togetherwith the aminourethanes include, in particular, the addition products ofpolyamines and (meth)acrylic acid derivatives, such as(meth)acrylonitrile, (meth)acrylic acid and C₁ -C₄ -alkyl estersthereof, and (meth)acrylamide. Addition products of this kind aredescribed in EP-A 0 000 605. If the aminourethanes are used togetherwith these addition products or with the above-mentioned amine curingagents, it may be advantageous also to use, in addition, the emulsifiersdescribed in EP-A 0 000 605 and/or DE-A 43 10 198. These emulsifiers canbe adducts of conventional polyepoxides and polyalkylene polyetherpolyols in a ratio of functional groups from 2:0.1 to 2:1.5. Theadditional use of these emulsifiers is advantageous when the bindersystem to be cured is an aqueous system. Determined by the ratio offunctional groups as indicated above, the emulsifier contains freeremaining epoxy groups. When such emulsifiers are used, this compoundreacts with the aminourethane and/or with the other amine curing agents.

The quantity of emulsifier generally is from 20 to 80% by weight of thetotal quantity of emulsifier and all the curing agents, calculated assolids. Correspondingly, the total quantity of curing agent can be from80 to 20%, in which context the ratio of emulsifier to curing agentshould be chosen such that, in each case, free amino groups, preferablyprimary amino groups, are still present after the reaction of theemulsifier with the curing agent.

The modification according to the invention of liquid two-componentsystems, preferably aqueous epoxy/amine systems, with the aminourethanesknown per se can be carried out in a variety of methods. A first methodcomprises employing the aminourethanes as an isolated compound either inpure form or in a solvent which is appropriate for the subsequentaqueous formulation. Examples of suitable solvents in this context aremonoalcohols such as benzyl alcohol, ether alcohols such asmethoxypropanol or isopropoxypropanol, and glycols such as methylglycol,butylglycol and butyldiglycol.

The procedure may be such that the aminourethane resin in pure form, forexample as a powder, or in the form of a solvent, is mixed orhomogenized with the aqueous amine curing agent, and this mixture isadded to the epoxy resin component. However, it also is possible to addthe aminourethane resin to the finished coating composition separately.Dissolved in a suitable form, the aminourethane can be added at anydesired point during the preparation of the coating composition.

A second method comprises forming a chemical compound from theaminourethane resin and the aqueous amine curing agent, and adding thisadduct as the amino component to the epoxy resin component. In thiscontext, the chemical linking of aminourethane and amine curing agent ispreferred over the mixture of aminourethane/amine curing agent or theseparate addition of the aminourethane. This second method preferably isemployed when, in addition to the aminourethane and further conventionalaqueous amine curing agents, the amine component of the two-componentsystem contains epoxy-containing emulsifiers of the type describedabove.

In turn, there are various possibilities for the chemical linkage ofaminourethane and amine curing agent. For instance, the aminourethanecan on the one hand be premixed with the other curing agents, and thismixture then chemically reacted with the emulsifier. A second variantcomprises chemically reacting the aminourethane with the emulsifier andthen adding the additional amine curing agent to the product.Conversely, it also is possible first to react chemically suchadditional amines with the emulsifier and then to admix theaminourethane. Finally, however, it is also possible first to react anamine mixture or amine curing agent mixture with a substoichiometricamount of compounds containing 2-oxo-1,3-dioxolane groups, and then toreact this product with a substoichiometric amount of emulsifier, or tocarry out this two-step reaction in reverse order.

In this context, care should be taken to ensure that the end productcontains a sufficient number of free, preferably primary, amino groups.The reactions mentioned above preferably can be carried out in theabsence of solvents, although in individual cases it may be entirelysensible to work in the presence of solvents, especially in order toadjust the viscosity to a favorable level. The reaction temperaturestypically are in the range of from 20° to 90° C. The ratios ofaminourethane curing agents to the conventional amine curing agents isgenerally in the range of between 95:5 and 5:95, preferably between80:20 and 20:80 and particularly preferably between 70:30 and 30:70.These figures also apply when the above-mentioned emulsifier is used.Those skilled in the art are capable of reacting the aforementionedcompounds using the methods described herein.

Epoxy resins preferably are employed as polyamine-crosslinking component(A) in the coating compositions according to the invention. These resinsmay be commercially available di- or polyepoxides. These arefilm-forming epoxy resins which are present as aqueous dispersion or aswater-dilutable resin. Examples of such polyepoxides are polyglycidalethers based on aliphatic or aromatic diols such as bisphenol A orbisphenol F, or polyalkylene glycols which are commercially availableand known to those skilled in the art. Preferred compounds in thiscontext are modified, nonionically stabilized epoxy resins based onaromatic diols, as described in, for example, DE-A 36 43 751.

The coating composition according to the invention comprises twodifferent components: the polyamine-crosslinking component (A),preferably an epoxy resin, and the polyamine curing agent (B) which ismodified with the aminourethane resin (C). Shortly before application,the two components are mixed in a ratio of amino groups to epoxy resinspreferably of from 5:1 to 1:5, and more preferably from 1.5:1 to 1:1.5.In calculating this ratio, the amino groups of the aminourethane shouldalso be taken into account.

The coating composition according to the invention can also containconventional pigments and fillers, for example titanium dioxide, bariumsulfate, aluminum silicate, silicon dioxide, zinc phosphate, carbonblack and chromophoric and/or transparent organic or inorganic pigments,as well as conventional auxiliaries. Examples of the latter areanticrater agents, antifoams, leveling agents, catalysts and adhesionpromoters. The coating composition may also contain organic solvents,the contents of which should preferably be below 10% by weight.

Suitable pigments and/or fillers may be dispersed either in the epoxyresin component or in the amine component. Their dispersion in the aminecomponent is preferred. Those skilled in the art are capable ofdispersing pigments and/or fillers in the epoxy resin using techniquesknown in the art.

It is advantageous for the coating compositions according to theinvention, especially aqueous coating compositions based onepoxide/amine, to contain one or more water-dilutable or water-solublepolyurethane resins having a number-average molar mass (M_(n)) of500-500,000 g/mol, in order to achieve surfaces which are free fromdefects. The use of 5-80% by weight of the polyurethane resin, based onthe resin solids content of epoxy resin and polyamine curing agent, alsois advantageous in the coating composition. The polyurethane resin maybe contained either in the epoxy component, in the polyamine componentor in both components. The aqueous polyurethane resin may be ionicallyor nonionically stabilized. Examples of such polyurethane resins aredescribed in DE-A 41 23 860.

In order to improve the properties it is also possible, instead of thepolyurethane resins, to add one or more water-soluble or water-dilutableacrylate resins. Such polyacrylate resins have, for example, anumber-average molar mass (M_(n)) of 500-200,000 g/mol. They arepreferably acrylate copolymers, with conventional water-soluble orwater-dilutable polyacrylate resins being appropriate. Examples of theseare described in EP-A 0 358 979.

The coating compositions according to the invention can be applied byconventional methods, such as dipping, rolling, brushing and spraying.Crosslinking can be carried out at temperatures of 20°-120° C., butpreferably at temperatures below 80° C.

After crosslinking, homogeneously coated substrates with smooth,defect-free surfaces are obtained. In comparison with known aqueousepoxy/polyamine systems, the coating compositions according to theinvention show a considerable reduction in thermoplasticity, leading toa marked improvement in sandability. After just a short drying time thecoatings can be wet- and dry-sanded.

A further advantage of the coating compositions according to theinvention is the very good adhesion to the substrate, even in thincoats, and in a very good wet adhesion to, for example, zinc, iron,steel, aluminum and glass fiber-reinforced plastics.

The coating composition according to the invention can be used forcoating a variety of substrates, for example metal, plastic, wood, glassand mineral substrates. A preferred application of the coatingcompositions is in the sector of automotive finishing and the coating ofautomotive components. In this context the coating compositions arepreferably applied as filler coats and/or primer coats.

The examples which follow are intended to illustrate the invention inmore detail.

EXAMPLES Example 1

Preparation of an aminourethane 1

BDC (916 g, the product of reaction of the diglycidyl ether of bisphenolA with carbon dioxide, until complete disappearance of the epoxidegroups) was heated to 120° C. together with 120 g of methylglycol, andmaintained at this temperature with thorough stirring. To the resultingsolution, which soon became almost clear, 103 g of diethylenetriamine(DETA) were first added at 100° C. and reaction was carried out to anamine number of 39 mg of KOH/g. Reaction was then continued with 120 gof ethylenediamine up to an amine number of 106 mg of KOH/g. Followingremoval of volatile compounds by distillation, 1176 g of productremained, with an amine number of 116 mg of KOH/g and 22% residualsolvent.

The melting point of the product was below room temperature.

Example 2

Preparation of an aminourethane 2

BDC (229 g) was heated to 120° C. together with 120 g of methylglycol,and maintained at this temperature with thorough stirring. The resultingsolution was reacted with 103 g of DETA until an amine number of 171 mgof KOH/g was reached. After removal of volatile compounds bydistillation, 420 g of product remained, having an amine number of 203mg of KOH/g, 1.5% residual solvent and a melting point of 42° C.

Example 3

Preparation of a chemically integrated aminourethane 3

A solution of 229 g of BDC in 95 g of butylglycol was reacted first with25.8 g of diethylenetriamine up to an amine number of 34 mg of KOH/g,and then reacted further with 30 g of ethylenediamine until an aminenumber of 106 mg of KOH/g was reached. This resulted in 380 g of productbeing obtained, having an amine number of 102 mg of KOH/g, containing25% butylglycol and being highly viscous at room temperature.

The resulting product (131.6 g) was heated to 70° C. together with 43.8g of isophoronediamine and 35.2 g of m-xylylenediamine, with thoroughstirring. The mixture, which was now clear and had an amine number of 95mg of KOH/g, was reacted with 155.2 g of an epoxy-functional emulsifieras described in DE 43 10 198 (Exp. 1.4), the reaction being considerablyexothermic. The mixture, which was still clear, was adjusted to a solidscontent of 80% using 59 g of water and had an amine number of 166 mg ofKOH/g and a viscosity of about 28,000 mPas (25° C.). The productcontained 7.8% butylglycol.

Example 4

Preparation of a filler 1

Aminourethane 1 (19 g), corresponding to Example 1, 23 g of acommercially available polyamine (80% in water, Beckopox VEM 2133W fromHoechst AG) and 350 g of fully deionized water were mixed thoroughlywith one another. A commercially available polyurethane thickener (13 g)and 1.3 g of a corrosion inhibitor were added to the mixture, and werelikewise mixed in thoroughly. The following pigments and fillers weredispersed in this mixture in a conventional manner:

    ______________________________________                                                 32 g of silicon dioxide                                                       114 g                                                                              of barium sulfate                                                        95 g of aluminum silicate                                                     104 g                                                                              of titanium dioxide                                                      5 g  of yellow iron oxide.                                           ______________________________________                                    

A commercially available nonionic polyurethane dispersion (123 g, solidscontent 40%, ZB 2081 UZ from DSM) was added to the resulting mixture,and intensive stirring was carried out. Shortly before application, 243g of a commercial aqueous epoxy resin (50%, ®Beckopox EP 384W fromHoechst AG) were added, and the two components were intensively mixed bystirring.

Example 5

Preparation of a filler 2

Aminourethane 2 (27 g), corresponding to Example 2, 25 g of a commercialpolyamine (80% in water, Beckopox VEM 2133W from Hoechst AG) and 336 gof fully deionized water were mixed thoroughly with one another. Acommercial polyurethane thickener (13 g) and 1.3 g of a corrosioninhibitor are added to the mixture, and were likewise mixed inthoroughly. The following pigments and fillers were dispersed in thismixture in a conventional manner:

    ______________________________________                                                 32 g of silicon dioxide                                                       114 g                                                                              of barium sulfate                                                        95 g of aluminum silicate                                                     104 g                                                                              of titanium dioxide                                                      5 g  of yellow iron oxide.                                           ______________________________________                                    

Shortly before application of the resulting polyamine component, 243 gof a commercial aqueous epoxy resin (50%, EP 384) were added, and thetwo components were mixed intensively by stirring.

Example 6

Preparation of a filler 3

Aminourethane 3 (48.5 g.), corresponding to Example 3, and 350 g offully deionized water were thoroughly mixed with one another. Acommercial polyurethane thickener (13 g) and 1.3 g of a corrosioninhibitor were added to the mixture and were likewise mixed inthoroughly. The following pigments and fillers were dispersed in thismixture in a conventional manner:

    ______________________________________                                                 32 g of silicon dioxide                                                       114 g                                                                              of barium sulfate                                                        95 g of aluminum silicate                                                     104 g                                                                              of titanium dioxide                                                      5 g  of yellow iron oxide.                                           ______________________________________                                    

Shortly before application, 238 g of a commercial aqueous epoxy resin(50%, ®Beckopox EP 384 from Hoechst AG) were added to the resultingpolyamine component, and the two components were mixed intensively bystirring.

Example 7 (comparative example)

Preparation of a filler 4

The polyamine component was prepared in analogy to Example 4, exceptthat 37 g of the commercially available polyamine curing agent weremixed with 334 g of fully deionized water without the addition ofaminourethane. As epoxy component, 262 g of a commercial aqueous epoxyresin (50% Beckopox, EP 384) were added shortly prior to application,and the two components were mixed intensively by stirring.

Example 8

Preparation of a primer 1

Aminourethane 1 (15 g), corresponding to Example 1, 283 g of fullydeionized water and 46 g of a commercial polyamine (80% in waterBeckopox, VEH 2133) were mixed thoroughly with one another. Acommercially available polyurethane thickener (7 g) and 10 g of acommercially available siccative were added to the mixture and werelikewise mixed in thoroughly. The following pigments and fillers weredispersed in this mixture in a conventional manner:

    ______________________________________                                        10 g      of silicic acid                                                     70 g      of a zinc-containing anticorrosion pigment                          30 g      of CaCO.sub.3                                                       78 g      of talc                                                             60 g      of yellow iron oxide.                                               ______________________________________                                    

A commercial aqueous epoxy resin (390 g. Beckopox, VEP 2385, 57%) wereadded shortly prior to application, and the two components were mixedintensively by stirring. Example 9

Preparation of a primer 2 (Comparison)

The procedure of Example 8 was followed, except that 57 g of thecommercially available polyamine and 280 g of fully deionized water weremixed with one another, without the addition of aminourethane. As theepoxy component, 399 g of a commercial epoxy resin (®Beckopox VEP 2385from Hoechst AG, 57%) were added shortly before application, and the twocomponents were mixed intensively with one another.

Application of the coating compositions

The filler-coating compositions were each applied by spraying to steelsubstrates coated beforehand with a cataphoretic primer and were driedat 60° C. for 1/2 hour. The primer-coating compositions were eachapplied to steel, zinc and aluminum substrates and were dried at 20° C.for 15 minutes. The properties of the resulting coatings are summarizedin the table below.

As can be seen from the table below, only the inventive fillers andprimer compositions exhibited very good wet and dry sanding afterrelatively short drying times (15 minutes-30 minutes).

    __________________________________________________________________________                           Filler 4                                               Coat thickness                                                                        Filler 1                                                                           Filler 2                                                                           Filler 3                                                                           (comparison) Primer 2                                  in μm                                                                              30/130                                                                             30/130                                                                             30/130                                                                             30/60  Primer 1                                                                            (comparison)                              __________________________________________________________________________    Wet sanding                                                                           ++/++                                                                              ++/++                                                                              ++/++                                                                              +/-                                                    Dry sanding                                                                           ++/++                                                                              ++/++                                                                              ++/++                                                                              +/-                                                    Adhesion to:                                                                  steel                         +     +                                         zinc                          +     -                                         aluminum                      +     -                                         GrP                           +     -                                         __________________________________________________________________________     ++ very good                                                                  + good                                                                        - poor                                                                        -- very poor                                                                  GrP: Glass fiberreinforced plastic                                       

While the invention has been described in detail by reference toparticularly preferred embodiments and examples, those skilled in theart recognize that various modifications can be made withoutsignificantly departing from the spirit and scope thereof. In addition,the disclosures of all of the aforementioned documents are incorporatedby reference herein in their entirety.

What is claimed is:
 1. A process for the production of a coatingcomposition which is crosslinkable at room temperature, comprising thesteps of (i) applying a layer of a coating composition comprising:A) oneor more resins having amino-reactive groups; B) one or more polyaminecuring agents; C) one or more aminourethanes comprising reactionproducts ofC1) oligomeric or polymeric compounds which contain at leastone terminal 2-oxo-1,3-dioxolane groups (cyclic carbonate groups), andC2) amines containing at least one primary amino group, the ratio ofnumbers of functional groups in C1) and C2) being from 1:1 to 1:10; andD) optionally, pigments, fillers, one or more organic solvents, waterand conventional additives to a substrate, wherein a chemical compoundis formed from a reaction between the aminourethane C) and the polyaminecuring agent B) prior to the following step (ii) and (ii) curing thecoating layer, wherein said reaction between said aminourethane C) andsaid polyamine curing agent B) is selected from the group consistingof(a) mixing the aminourethane C) with the polyamine curing agent B),and then reacting this mixture with an emulsifier D); (b) reacting theaminourethane C) with an emulsifier D), and then adding the amine curingagent B); and (c) reacting the amine curing agent B) with an emulsifierD), and then adding the aminourethane C), wherein the emulsifier D) isan adduct of polyepoxides and polyalkylene ether polyols in a ratio ofnumbers of functional groups of from 2:0.1 to 2:1.5.
 2. The process asclaimed in claim 1, wherein said reaction between said aminourethane C)and said polyamine curing agent B) comprises the steps of:1) mixing saidaminourethane C) and said polyamine curing agent B) to produce amixture, and; 2) reacting said mixture with said emulsifier.
 3. Theprocess as claimed in claim 1, wherein said reaction between saidaminourethane C) and said polyamine curing agent B) comprises the stepsof:1) reacting said aminourethane C) with said emulsifier to produce areaction product; and 2) mixing said polyamine curing agent with saidreaction product.
 4. The process as claimed in claim 1, wherein saidreaction between said aminourethane C) and said polyamine curing agentB) comprises the steps of:1) reacting said polyamine curing agent B)with said emulsifier to produce an amine reaction product; and 2) mixingsaid aminourethane C) with said amine reaction product.